After loading the Nikon View software I was able to view the files via Nikon view and also using Adobe Bridge and process with ACR. Thanks to all - maybe the moral is - Read the manual and don't assume that everything is the same as previously.

I only use Nikon Transfer to renumbering the file to an id with my preferred format (yyyymmdd-nnnn). LR will do that but since I have LR3

Not sure if you already know this, but since you said you are going through Adobe Bridge, Bridge CS5 has a powerful Tools > Batch Rename command (better than Lightroom's rename in some ways), so that you don't have to rename with Lightroom or Nikon Transfer.

I only use Nikon Transfer to renumbering the file to an id with my preferred format (yyyymmdd-nnnn). LR will do that but since I have LR3

Not sure if you already know this, but since you said you are going through Adobe Bridge, Bridge CS5 has a powerful Tools > Batch Rename command (better than Lightroom's rename in some ways), so that you don't have to rename with Lightroom or Nikon Transfer.

Very true. I've not bothered to even install any Nikon software on my computer - no need as the various Adobe applications do the same job, and often more efficently too. You could also use the Adobe Photodownloaded (comes with Bridge/PS) to transfer files from the card to your hard drive (or LR, as ssprengel notes); no need to even use Windows Explorer or Mac Finder.

I have downloaded and installed ACR 7.1 but it is only partially functional with regards to my D800 NEFs. For example, in the Filmstrip workspace, it will generate thumbnails of the NEFs and, when double-clicked, ACR is launched and I can post-process the NEF. However, when I simply select a particular NEF, a preview of the image does not appear only a generic NEF icon. I tried to insert a screen capture showing this but was informed that this type of content wasn't allowed.

ACR only supports interpretation of NEFs within an Adobe product. When you are using a file selection dialog to choose files, this is Adobe using an OS-level function, not Bridge or Photoshop, so you will need an update to the OS or provide it an OS-level plug-in to show the previews, with the link in the other reply being a possible choice.

If you are saying that Previews within an Adobe product are not showing, perhaps the ACR cache needs cleared.

I'm stuck here too, I have a new iMac, the Adobe Photoshop suite Cs5 and a new nikon D800. I can't open my nef files either, not in PS, Bridge, Lightroom. I've tried to install ACR 7.1 and I'm told I don't need it by an error. I installed the earlier version of ACR and that doesn't help. So now what? I got lost and missed the solution to the problem.